An important issues in conservation biology is how dispersal among populations influences the persistence of species in a fragmented landscape. Molofsky and Ferdy (2005) measured this in the annual plant Cardamine pensylvanica, a weed that produces explosively dispersed seeds. Four treatments were used to manipulate seed dispersal by changing the distance among experimental plant populations. These treatments were adjacent (continuous) separated by 23.2 cm (medium), separated by 49.5 cm (long) or separated by partitions that blocked all seed dispersal among populations (isolated). Treatments were randomly assigned to plant populations. The data below are the number of generations that the populations persisted in four replicates of each treatment. Isolated: 13, 8, 8, 8 Medium: 14, 12, 16,16 Long: 13, 9, 10, 11 Continuous: 9,13,13,16